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Lacy Bryozoan Lacy Bryozoan Lacy Bryozoan 

  Scientific Name:

Membranipora membranacea

 Common Name:

Lacy crust bryozoan (also: lace bryozoan, crust bryozoan)

 Native Range:

M. membranaceais native to the temperate waters of Europe and to the Pacific Coast of North America.

 Established Range:

On the East Coast, the lacy crust bryozoan can be found from Nova Scotia to the Long Island Sound.

 Established in Rhode Island?

Yes, throughout Narragansett Bay

 Date and Location of Introduction:

1987, Isles of Shoals, ME

 Method of Introduction:

Unknown, but most likely aquaculture or ballast water


M. membranacea inhabits shallow marine waters, where it attaches itself to the blades of macroalgae in large colonies.


M. membranacea is capable of reproducing sexually via broadcast spawning in the spring and summer. It can also reproduce asexually by budding new zooids (a zooid is an individual).


M. membranacea is considered a problematic species because of the negative impacts it has on kelp forests. When it invades a kelp forest, it forms thick crusts on kelp blades. These blades are highly prone to breaking during storms, which causes an overall decline in kelp density. Because kelp forests are an important source of food and shelter for many marine organisms, any loss of kelp can have a major negative impact on the marine environment. M. membranacea is also known to crowd out native bryozoans and other epiphytes, and reduced sea urchin populations have been reported in kelp forests where M. membranacea has invaded.


There are no known effective control methods at this time.

 Identification Card:

Courtesy of Salem Sound Coastwatch


 Works Cited:

O'Connell, D. and P. Fuller. 2010.   Membranipora  membranacea. USGS Nonindigenous Aquatic Species Database, Gainesville, FL.

Scheibling, R.E. 2001. Membranipora membranacea. Marine Invasive Species in Nova Scotia. Benthic Ecology Lab, Dalhousie University, Halifax, NS.